This research is directed at identification of pathogenic components of gonococci, how these components work, and how the host responds to them. During the present grant period, results indicated: (1) Virulent gonococci have two antiphagocytic components. One, the pili, is dominant. The second is expressed only after pili are removed, is sensitive to treatment with EDTA, and depends on the lipopolysaccharide of the envelope. (2) Attachment of virulent gonococci to leukocytes cause release of lysosomal enzymes to the cell exterior. (4) The major phospholipids of gonococcal membranes contain phospholipase. Further research will involve: (1) study if the immunology of the EDTA-sensitive antiphagocytic activity, (2) search for the way that EDTA alters resistance to phagocytosis, and (3) continued examination of the interaction of gonococci and leukocytes, especially leukocytic gonococcidal activity and the exocytosis of lysosomal contents. BIBLIOGRAPHIC REFERENCES: Sawyer, W.D., Fulbright, R.S., Eads, M.E., and Wegener, W.S., Studies on the antiphagocytic properties of gonococci. Abstracts Ann. Mtg. Am. Soc. Microbiol. 1975. 13. Rosentahl, R.S., Wegener, W.S., and Sawyer, W.D., Conditions for studying EDTA-dependent release of macromolecules in Neisseria gonorrhoeae. Abstracts Ann. Mtg. Am. Soc. Microbiol. 1975, 13.